diff --git a/cdrstats/metrics.go b/cdrstats/metrics.go
index f15752bad..2f37b6bdb 100644
--- a/cdrstats/metrics.go
+++ b/cdrstats/metrics.go
@@ -26,13 +26,17 @@ type Metric interface {
 	GetValue() float64
 }
 
+const ASR = "ASR"
+const ACD = "ACD"
+const ACC = "ACC"
+
 func CreateMetric(metric string) Metric {
 	switch metric {
-	case "ASR":
+	case ASR:
 		return &ASRMetric{}
-	case "ACD":
+	case ACD:
 		return &ACDMetric{}
-	case "ACC":
+	case ACC:
 		return &ACCMetric{}
 	}
 	return nil
diff --git a/cdrstats/stats.go b/cdrstats/stats.go
index e5d99a212..c4c61b372 100644
--- a/cdrstats/stats.go
+++ b/cdrstats/stats.go
@@ -41,6 +41,9 @@ type QCDR struct {
 }
 
 func NewStatsQueue(conf *config.CdrStatsConfig) *StatsQueue {
+	if conf == nil {
+		return &StatsQueue{metrics: make(map[string]Metric)}
+	}
 	sq := &StatsQueue{
 		conf:    conf,
 		metrics: make(map[string]Metric, len(conf.Metrics)),
@@ -58,17 +61,17 @@ func (sq *StatsQueue) AppendCDR(cdr *utils.StoredCdr) {
 	if sq.AcceptCDR(cdr) {
 		qcdr := sq.SimplifyCDR(cdr)
 		sq.cdrs = append(sq.cdrs, qcdr)
-		sq.AddToMetrics(qcdr)
+		sq.addToMetrics(qcdr)
 	}
 }
 
-func (sq *StatsQueue) AddToMetrics(cdr *QCDR) {
+func (sq *StatsQueue) addToMetrics(cdr *QCDR) {
 	for _, metric := range sq.metrics {
 		metric.AddCDR(cdr)
 	}
 }
 
-func (sq *StatsQueue) RemoveFromMetrics(cdr *QCDR) {
+func (sq *StatsQueue) removeFromMetrics(cdr *QCDR) {
 	for _, metric := range sq.metrics {
 		metric.RemoveCDR(cdr)
 	}
@@ -87,13 +90,13 @@ func (sq *StatsQueue) PurgeObsoleteCDRs() {
 	currentLength := len(sq.cdrs)
 	if currentLength > sq.conf.QueuedItems {
 		for _, cdr := range sq.cdrs[:currentLength-sq.conf.QueuedItems] {
-			sq.RemoveFromMetrics(cdr)
+			sq.removeFromMetrics(cdr)
 		}
 		sq.cdrs = sq.cdrs[currentLength-sq.conf.QueuedItems:]
 	}
 	for i, cdr := range sq.cdrs {
 		if time.Now().Sub(cdr.SetupTime) > sq.conf.TimeWindow {
-			sq.RemoveFromMetrics(cdr)
+			sq.removeFromMetrics(cdr)
 			continue
 		} else {
 			if i > 0 {
diff --git a/cdrstats/stats_test.go b/cdrstats/stats_test.go
index e5f85cd13..994092ae1 100644
--- a/cdrstats/stats_test.go
+++ b/cdrstats/stats_test.go
@@ -17,3 +17,159 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 */
 
 package cdrstats
+
+import (
+	"testing"
+	"time"
+
+	"github.com/cgrates/cgrates/config"
+	"github.com/cgrates/cgrates/utils"
+)
+
+func TestStatsInit(t *testing.T) {
+	sq := NewStatsQueue(&config.CdrStatsConfig{Metrics: []string{ASR, ACC}})
+	if len(sq.metrics) != 2 {
+		t.Error("Expected 2 metrics got ", len(sq.metrics))
+	}
+}
+
+func TestStatsValue(t *testing.T) {
+	sq := NewStatsQueue(&config.CdrStatsConfig{Metrics: []string{ASR, ACD, ACC}})
+	cdr := &utils.StoredCdr{
+		AnswerTime: time.Date(2014, 7, 14, 14, 25, 0, 0, time.UTC),
+		Usage:      10 * time.Second,
+		Cost:       1,
+	}
+	sq.AppendCDR(cdr)
+	cdr.Cost = 2
+	sq.AppendCDR(cdr)
+	cdr.Cost = 3
+	sq.AppendCDR(cdr)
+	s := sq.GetStats()
+	if s[ASR] != 100 ||
+		s[ACD] != 10 ||
+		s[ACC] != 2 {
+		t.Errorf("Error getting stats: %+v", s)
+	}
+}
+
+func TestStatsSimplifyCDR(t *testing.T) {
+	cdr := &utils.StoredCdr{
+		TOR:            "tor",
+		AccId:          "accid",
+		CdrHost:        "cdrhost",
+		CdrSource:      "cdrsource",
+		ReqType:        "reqtype",
+		Direction:      "direction",
+		Tenant:         "tenant",
+		Category:       "category",
+		Account:        "account",
+		Subject:        "subject",
+		Destination:    "12345678",
+		SetupTime:      time.Date(2014, 7, 3, 13, 43, 0, 0, time.UTC),
+		Usage:          10 * time.Second,
+		MediationRunId: "mri",
+		Cost:           10,
+	}
+	sq := &StatsQueue{}
+	qcdr := sq.SimplifyCDR(cdr)
+	if cdr.SetupTime != qcdr.SetupTime ||
+		cdr.AnswerTime != qcdr.AnswerTime ||
+		cdr.Usage != qcdr.Usage ||
+		cdr.Cost != qcdr.Cost {
+		t.Error("Failed to simplify cdr: %+v", qcdr)
+	}
+}
+
+func TestAcceptCDR(t *testing.T) {
+	sq := NewStatsQueue(nil)
+	cdr := &utils.StoredCdr{
+		TOR:            "tor",
+		AccId:          "accid",
+		CdrHost:        "cdrhost",
+		CdrSource:      "cdrsource",
+		ReqType:        "reqtype",
+		Direction:      "direction",
+		Tenant:         "tenant",
+		Category:       "category",
+		Account:        "account",
+		Subject:        "subject",
+		Destination:    "12345678",
+		SetupTime:      time.Date(2014, 7, 3, 13, 43, 0, 0, time.UTC),
+		Usage:          10 * time.Second,
+		MediationRunId: "mri",
+		Cost:           10,
+	}
+	sq.conf = &config.CdrStatsConfig{}
+	if sq.AcceptCDR(cdr) != true {
+		t.Error("Should have accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{TOR: []string{"test"}}
+	if sq.AcceptCDR(cdr) == true {
+		t.Error("Should have NOT accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{CdrHost: []string{"test"}}
+	if sq.AcceptCDR(cdr) == true {
+		t.Error("Should have NOT accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{CdrSource: []string{"test"}}
+	if sq.AcceptCDR(cdr) == true {
+		t.Error("Should have NOT accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{Direction: []string{"test"}}
+	if sq.AcceptCDR(cdr) == true {
+		t.Error("Should have NOT accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{Tenant: []string{"test"}}
+	if sq.AcceptCDR(cdr) == true {
+		t.Error("Should have NOT accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{Category: []string{"test"}}
+	if sq.AcceptCDR(cdr) == true {
+		t.Error("Should have NOT accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{Account: []string{"test"}}
+	if sq.AcceptCDR(cdr) == true {
+		t.Error("Should have NOT accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{Subject: []string{"test"}}
+	if sq.AcceptCDR(cdr) == true {
+		t.Error("Should have NOT accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{DestinationPrefix: []string{"test"}}
+	if sq.AcceptCDR(cdr) == true {
+		t.Error("Should have NOT accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{DestinationPrefix: []string{"test", "123"}}
+	if sq.AcceptCDR(cdr) != true {
+		t.Error("Should have accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{SetupInterval: []time.Time{time.Date(2014, 7, 3, 13, 43, 0, 1, time.UTC)}}
+	if sq.AcceptCDR(cdr) == true {
+		t.Error("Should have NOT accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{SetupInterval: []time.Time{time.Date(2014, 7, 3, 13, 42, 0, 0, time.UTC), time.Date(2014, 7, 3, 13, 43, 0, 0, time.UTC)}}
+	if sq.AcceptCDR(cdr) == true {
+		t.Error("Should have NOT accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{SetupInterval: []time.Time{time.Date(2014, 7, 3, 13, 42, 0, 0, time.UTC)}}
+	if sq.AcceptCDR(cdr) != true {
+		t.Error("Should have accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{SetupInterval: []time.Time{time.Date(2014, 7, 3, 13, 42, 0, 0, time.UTC), time.Date(2014, 7, 3, 13, 43, 0, 1, time.UTC)}}
+	if sq.AcceptCDR(cdr) != true {
+		t.Error("Should have accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{UsageInterval: []time.Duration{11 * time.Second}}
+	if sq.AcceptCDR(cdr) == true {
+		t.Error("Should have NOT accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{UsageInterval: []time.Duration{1 * time.Second, 10 * time.Second}}
+	if sq.AcceptCDR(cdr) == true {
+		t.Error("Should have NOT accepted thif CDR: %+v", cdr)
+	}
+	sq.conf = &config.CdrStatsConfig{UsageInterval: []time.Duration{10 * time.Second, 11 * time.Second}}
+	if sq.AcceptCDR(cdr) != true {
+		t.Error("Should have accepted thif CDR: %+v", cdr)
+	}
+}